Method and apparatus for configuration of reference signal

ABSTRACT

Provided herein are method and apparatus for configuration of a Reference Signal (RS) and a Tracking Reference Signal (TRS). An embodiment provides a method for a user equipment (UE), including determining a number of slots for a Tracking Reference Signal (TRS), wherein the number of slots is based on a subcarrier spacing of a bandwidth part (BWP) in a current component carrier for the UE; and receiving TRS based on the number of slots and a quasi co-location (QCL) relationship of the TRS, wherein the QCL relationship indicates that the TRS is Quasi-Co-Located (QCLed) with a Synchronization Signal (SS) block or a Channel State Information Reference Signal (CSI-RS).

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 17/895,163filed Aug. 25, 2022, which is a Continuation of application Ser. No.16/646,176 filed Mar. 11, 2020 (now U.S. Pat. No. 11,464,075, issued onOct. 4, 2022). which claims priority to International Application No.PCT/CN2018/104791 filed on Sep. 10, 2018, entitled “METHOD AND APPARATUSFOR CONFIGURATION OF REFERENCE SIGNAL”, which claims priority toInternational Application No. PCT/CN2017/105240 filed on Oct. 3, 2017,entitled “USER EQUIPMENT SUGGESTED REFERENCE SIGNAL CONFIGURATION”, andInternational Application No. PCT/CN2017/101209 filed on Sep. 11, 2017,entitled “TRACKING REFERENCE SIGNAL CONFIGURATION”, which areincorporated by reference herein in their entirety for all purposes.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to a method andapparatus for wireless communications, and in particular to a method andapparatus for configuration of a Reference Signal (RS) and a TrackingReference Signal (TRS).

BACKGROUND ART

In a Multiple-Input and Multiple-Output (MIMO) system (such as a fifthgeneration (5G) system) operating in high band (e.g., above 6 GHz),analog beamforming can be applied. An access node (such as a nextGeneration NodeB (gNB)) and a user equipment (UE) may each maintain aplurality of beams. There may be multiple beam pair links (BPLs) betweenthe access node and the UE, which can provide a good beamforming gain. Agood BPL can help to increase link budget. A beam management procedurecan be used to find out a good BPL (such as a good gNB-UE BPL). Somebeam sweeping based reference signals, such as a Synchronization Signal(SS) block and a Channel State Information Reference Signal (CSI-RS),can be used to assist in the beam management procedure to find out agood BPL. It is possible to apply wide beams for SS blocks, and theaccess node may configure some CSI-RS resources with narrow beams on topof the best SS block(s). Further, the access node may configure a subsetof SS block beams or resources among all the SS block beams or resourcesfor beam measurement, so as to reduce the number of SS block beams orresources to be measured by the UE. The access node may also configure asubset of CSI-RS beams or resources among all the CSI-RS beams orresources for beam measurement, so as to reduce the number of CSI-RSbeams or resources to be measured by the UE. Therefore, if only a subsetof beams or resources is configured for a UE's beam measurement, thereis a need to find out some new better beams outside of the configuredbeams or resources when necessary.

A Tracking Reference Signal (TRS) may be used for fine time and/orfrequency offset tracking for a MIMO system (such as a 5G system). OneTRS instance may be transmitted in N slots, and a UE may estimate aDoppler spread by using the TRS within the N slots, to estimate a timeand/or frequency offset. Estimation of a time offset may be based on anaverage estimation for each of symbols for a TRS instance. Therefore, itis important and necessary to determine a value of N, namely the numberof slots for a TRS instance. Further, for a multi Transmission ReceptionPoints (multi-TRP) operation, a UE should measure a time and/orfrequency offset for different TRPs. However different TRPs may havedifferent numerologies or different time offset. In the case ofmeasuring a time and/or frequency offset for an assistant TRP (such asan assistant gNB or a neighbor gNB) for a multi-TRP operation, a UE maynot be able to receive a signal from a current TRP (such as a currentgNB). Therefore, there is a need to provide time and/or frequency offsettracking for multiple TRPs. In addition, a multi-beam operation may beapplied to a TRS, and different beams may have different time and/orfrequency offset. Therefore, there is a need to identify a beam of eachTRS.

SUMMARY

An embodiment of the disclosure provides an apparatus for an access nodeincluding a radio frequency (RF) interface; and processing circuitryconfigured to: determine a time density of a Tracking Reference Signal(TRS) based on a subcarrier spacing of a bandwidth part (BWP) in acurrent component carrier for a user equipment (UE); determine afrequency density of the TRS based on a bandwidth of the TRS; determinea quasi co-location (QCL) relationship of the TRS; and encode the TRSbased on at least one of the time density, the frequency density and theQCL relationship for transmission to the UE via the RF interface.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure will be illustrated, by way of example andnot limitation, in the figures of the accompanying drawings in whichlike reference numerals refer to similar elements.

FIG. 1 illustrates an architecture of a system of a network inaccordance with some embodiments of the disclosure.

FIG. 2 illustrates an example for one or more BPLs between a UE and anaccess node in accordance with some embodiments of the disclosure.

FIG. 3 is a flow chart showing operations for configuration of a RS forbeam management in accordance with some embodiments of the disclosure.

FIG. 4A illustrates an example beam pattern for SS blocks and CSI-RSs inaccordance with some embodiments of the disclosure.

FIG. 4B illustrates an example SS block configuration in accordance withsome embodiments of the disclosure.

FIG. 4C illustrates an example CSI-RS configuration in accordance withsome embodiments of the disclosure.

FIG. 5 is a flow chart showing a method performed by a UE forconfiguration of a RS for beam management in accordance with someembodiments of the disclosure.

FIG. 6 is a flow chart showing operations for configuration of a TRS fortime and/or frequency offset tracking.

FIG. 7A illustrates an example of a TRS pattern in accordance with someembodiments of the disclosure.

FIG. 7B illustrates an example for multiplexing of different TRSresources in a FDM manner in accordance with some embodiments of thedisclosure.

FIG. 7C illustrates an example for multiplexing of different TRSresources in a TDM manner in accordance with some embodiments of thedisclosure.

FIG. 8 is a flow chart showing a method performed by an access node forconfiguration of a TRS for time and/or frequency offset tracking inaccordance with some embodiments of the disclosure.

FIG. 9 is a flow chart showing a method performed by a UE forconfiguration of a TRS for time and/or frequency offset in accordancewith some embodiments of the disclosure.

FIG. 10 illustrates example components of a device in accordance withsome embodiments of the disclosure.

FIG. 11 illustrates example interfaces of baseband circuitry inaccordance with some embodiments.

FIG. 12 is an illustration of a control plane protocol stack inaccordance with some embodiments.

FIG. 13 is a block diagram illustrating components, according to someexample embodiments, able to read instructions from a machine-readableor computer-readable medium and perform any one or more of themethodologies discussed herein.

DETAILED DESCRIPTION OF EMBODIMENTS

Various aspects of the illustrative embodiments will be described usingterms commonly employed by those skilled in the art to convey thesubstance of their work to others skilled in the art. However, it willbe apparent to those skilled in the art that many alternate embodimentsmay be practiced using portions of the described aspects. For purposesof explanation, specific numbers, materials, and configurations are setforth in order to provide a thorough understanding of the illustrativeembodiments. However, it will be apparent to those skilled in the artthat alternate embodiments may be practiced without the specificdetails. In other instances, well known features may have been omittedor simplified in order to avoid obscuring the illustrative embodiments.

Further, various operations will be described as multiple discreteoperations, in turn, in a manner that is most helpful in understandingthe illustrative embodiments; however, the order of description shouldnot be construed as to imply that these operations are necessarily orderdependent. In particular, these operations need not be performed in theorder of presentation.

The phrase “in an embodiment” is used repeatedly herein. The phrasegenerally does not refer to the same embodiment; however, it may. Theterms “comprising,” “having,” and “including” are synonymous, unless thecontext dictates otherwise. The phrases “A or B” and “A/B” mean “(A),(B), or (A and B).”

As discussed previously, some reference signals which can support a beamsweeping operation (such as an SS block and a CSI-RS) can be used toassist in a beam management procedure to find out one or more good BPLsbetween an access node (such as a gNB) and a UE. It is possible to applywide beams for SS blocks, and the access node may configure some CSI-RSresources with narrow beams on top of the best SS block(s). The accessnode may configure a subset of SS block beams or resources among all theSS block beams or resources for beam measurement, and may also configurea subset of CSI-RS beams or resources among all the CSI-RS beams orresources for beam measurement, so as to reduce the number of SS blockor CSI-RS beams or resources to be measured by the UE. In the case thatonly a subset of beams or resources are configured for a UE's beammeasurement, if beam quality of beams in the configured subset of beamsor resources are not good enough, there is a need to find out one ormore beams not within the configured subset that have better beamquality.

The present disclosure provides approaches for configuration of a RS forbeam management. In accordance with some embodiments of the disclosure,a plurality of RSs received via a plurality of beams of an access nodefor the plurality of RSs may be decoded. First beam quality for each ofa predefined subset of beams among the plurality of beams may then bedetermined based on the decoded RSs, and second beam quality for thepredefined subset of beams (namely, overall beam quality for thepredefined subset of beams) may be determined based on all of the firstbeam quality. In response to the second beam quality is below apredetermined threshold, third beam quality for each of one or morebeams among the plurality of beams that are not within the predefinedsubset may be determined based on the decoded RSs. A message may beencoded based on the first and third beam quality for transmission tothe access node for beam management, wherein the message identifies oneor more beam indexes for one or more SS blocks.

As discussed previously, a TRS may be used for fine time and/orfrequency offset tracking for a MIMO system (such as a 5G system). OneTRS instance may be transmitted in N slots, and a UE may estimate aDoppler spread by using the TRS within the N slots, to estimate a timeand/or frequency offset. Estimation of a time offset may be based on anaverage estimation for each of symbols for a TRS instance. Therefore, itis important and necessary to determine a value of N, namely the numberof slots for a TRS instance. Further, for a multi-TRP operation, a UEshould measure a time and/or frequency offset for different TRPs.However different TRPs may have different numerologies or different timeoffset. In the case of measuring a time and/or frequency offset for anassistant TRP (such as an assistant gNB or a neighbor gNB) for amulti-TRP operation, a UE may not be able to receive a signal from acurrent TRP (such as a current gNB). Therefore, there is a need toprovide a time and/or frequency offset tracking for multiple TRPs. Inaddition, a multi-beam operation may be applied to a TRS, and differentbeams may have different time and/or frequency offset. Therefore, thereis a need to identify a beam of each TRS.

The present disclosure provides approaches for configuration of a TRS.In accordance with some embodiments of the disclosure, a time density ofa TRS may be determined based on a subcarrier spacing of a bandwidthpart (BWP) in a current component carrier for a UE, a frequency densityof the TRS may be determined based on a bandwidth of the TRS, and aquasi co-location (QCL) relationship of the TRS may be determined. Thenthe TRS may be encoded based on at least one of the time density, thefrequency density and the QCL relationship for transmission to the UE.

FIG. 1 illustrates an architecture of a system 100 of a network inaccordance with some embodiments. The system 100 is shown to include auser equipment (UE) 101. The UE 101 is illustrated as a smartphone(e.g., handheld touchscreen mobile computing devices connectable to oneor more cellular networks), but may also include any mobile ornon-mobile computing device, such as a personal data assistant (PDA), atablet, a pager, a laptop computer, a desktop computer, a wirelesshandset, or any computing device including a wireless communicationsinterface.

The UE 101 may be configured to connect, e.g., communicatively couple,with a radio access network (RAN) 110, which may be, for example, anEvolved Universal Mobile Telecommunications System (UMTS) TerrestrialRadio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some othertype of RAN. The UE 101 may utilize a connection 103 which comprises aphysical communications interface or layer (discussed in further detailbelow); in this example, the connection 103 is illustrated as an airinterface to enable communicative coupling and may be consistent withcellular communications protocols, such as a Global System for MobileCommunications (GSM) protocol, a Code-Division Multiple Access (CDMA)network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular(POC) protocol, a Universal Mobile Telecommunications System (UMTS)protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation(5G) protocol, a New Radio (NR) protocol, and the like.

The RAN 110 may include one or more access nodes (ANs) that enable theconnection 103. These access nodes may be referred to as base stations(BSs), NodeBs, evolved NodeBs (eNBs), next Generation NodeBs (gNB), RANnodes, and so forth, and may include ground stations (e.g., terrestrialaccess points) or satellite stations providing coverage within ageographic area (e.g., a cell). As shown in FIG. 1 , for example, theRAN 110 may include AN 111 and AN 112. The AN 111 and AN 112 maycommunicate with one another via an X2 interface 113. The AN 111 and AN112 may be macro ANs which may provide lager coverage. Alternatively,they may be femtocell ANs or picocell ANs, which may provide smallercoverage areas, smaller user capacity, or higher bandwidth compared tomacro ANs. For example, one or both of the AN 111 and AN 112 may be alow power (LP) AN. In an embodiment, the AN 111 and AN 112 may be thesame type of AN. In another embodiment, they are different types of ANs.

Any of the ANs 111 and 112 may terminate the air interface protocol andmay be the first point of contact for the UE 101. In some embodiments,any of the ANs 111 and 112 may fulfill various logical functions for theRAN 110 including, but not limited to, radio network controller (RNC)functions such as radio bearer management, uplink and downlink dynamicradio resource management and data packet scheduling, and mobilitymanagement.

In accordance with some embodiments, the UE 101 may be configured tocommunicate using Orthogonal Frequency-Division Multiplexing (OFDM)communication signals with any of the ANs 111 and 112 or with other UEs(not shown) over a multicarrier communication channel in accordancevarious communication techniques, such as, but not limited to, anOrthogonal Frequency-Division Multiple Access (OFDMA) communicationtechnique (e.g., for downlink communications) or a Single CarrierFrequency Division Multiple Access (SC-FDMA) communication technique(e.g., for uplink and Proximity-Based Service (ProSe) or sidelinkcommunications), although the scope of the embodiments is not limited inthis respect. The OFDM signals may include a plurality of orthogonalsubcarriers.

In some embodiments, a downlink resource grid may be used for downlinktransmissions from any of the ANs 111 and 112 to the UE 101, whileuplink transmissions may utilize similar techniques. The grid may be atime-frequency grid, called a resource grid or time-frequency resourcegrid, which is the physical resource in the downlink in each slot. Sucha time-frequency plane representation is a common practice for OFDMsystems, which makes it intuitive for radio resource allocation. Eachcolumn and each row of the resource grid corresponds to one OFDM symboland one OFDM subcarrier, respectively. The duration of the resource gridin the time domain corresponds to one slot in a radio frame. Thesmallest time-frequency unit in a resource grid is denoted as a resourceelement. Each resource grid comprises a number of resource blocks, whichdescribe the mapping of certain physical channels to resource elements.Each resource block comprises a collection of resource elements; in thefrequency domain, this may represent the smallest quantity of resourcesthat currently can be allocated. There are several different physicaldownlink channels that are conveyed using such resource blocks.

The physical downlink shared channel (PDSCH) may carry user data andhigher-layer signaling to the UE 101. The physical downlink controlchannel (PDCCH) may carry information about the transport format andresource allocations related to the PDSCH channel, among other things.It may also inform the UE 101 about the transport format, resourceallocation, and H-ARQ (Hybrid Automatic Repeat Request) informationrelated to the uplink shared channel. Typically, downlink scheduling(assigning control and shared channel resource blocks to the UE 101within a cell) may be performed at any of the ANs 111 and 112 based onchannel quality information fed back from the UE 101. The downlinkresource assignment information may be sent on the PDCCH used for (e.g.,assigned to) the UE 101.

The PDCCH may use control channel elements (CCEs) to convey the controlinformation. Before being mapped to resource elements, the PDCCHcomplex-valued symbols may first be organized into quadruplets, whichmay then be permuted using a sub-block interleaver for rate matching.Each PDCCH may be transmitted using one or more of these CCEs, whereeach CCE may correspond to nine sets of four physical resource elementsknown as resource element groups (REGs). Four Quadrature Phase ShiftKeying (QPSK) symbols may be mapped to each REG. The PDCCH may betransmitted using one or more CCEs, depending on the size of thedownlink control information (DCI) and the channel condition. There maybe four or more different PDCCH formats defined in LTE with differentnumbers of CCEs (e.g., aggregation level, L=1, 2, 4, or 8).

Some embodiments may use concepts for resource allocation for controlchannel information that are an extension of the above-describedconcepts. For example, some embodiments may utilize an enhanced physicaldownlink control channel (EPDCCH) that uses PDSCH resources for controlinformation transmission. The EPDCCH may be transmitted using one ormore enhanced control channel elements (ECCEs). Similar to above, eachECCE may correspond to nine sets of four physical resource elementsknown as an enhanced resource element groups (EREGs). An ECCE may haveother numbers of EREGs in some situations.

The RAN 110 is shown to be communicatively coupled to a core network(CN) 120 via an S1 interface 114. In some embodiments, the CN 120 may bean evolved packet core (EPC) network, a NextGen Packet Core (NPC)network, or some other type of CN. In an embodiment, the S1 interface114 is split into two parts: the S1-mobility management entity (MME)interface 115, which is a signaling interface between the ANs 111 and112 and MMEs 121; and the S1-U interface 116, which carries traffic databetween the ANs 111 and 112 and the serving gateway (S-GW) 122.

In an embodiment, the CN 120 may comprise the MMEs 121, the S-GW 122, aPacket Data Network (PDN) Gateway (P-GW) 123, and a home subscriberserver (HSS) 124. The MMEs 121 may be similar in function to the controlplane of legacy Serving General Packet Radio Service (GPRS) SupportNodes (SGSN). The MMEs 121 may manage mobility aspects in access such asgateway selection and tracking area list management. The HSS 124 maycomprise a database for network users, including subscription-relatedinformation to support the network entities' handling of communicationsessions. The CN 120 may comprise one or several HSSs 124, depending onthe number of mobile subscribers, on the capacity of the equipment, onthe organization of the network, etc. For example, the HSS 124 canprovide support for routing/roaming, authentication, authorization,naming/addressing resolution, location dependencies, etc.

The S-GW 122 may terminate the S1 interface 113 towards the RAN 110, androutes data packets between the RAN 110 and the CN 120. In addition, theS-GW 122 may be a local mobility anchor point for inter-AN handovers andalso may provide an anchor for inter-3GPP mobility. Otherresponsibilities may include lawful intercept, charging, and some policyenforcement.

The P-GW 123 may terminate a SGi interface toward a PDN. The P-GW 123may route data packets between the CN 120 and external networks such asa network including an application server (AS) 130 (alternativelyreferred to as application function (AF)) via an Internet Protocol (IP)interface 125. Generally, the application server 130 may be an elementoffering applications that use IP bearer resources with the core network(e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). Inan embodiment, the P-GW 123 is communicatively coupled to an applicationserver 130 via an IP communications interface 125. The applicationserver 130 may also be configured to support one or more communicationservices (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTTsessions, group communication sessions, social networking services,etc.) for the UE 101 via the CN 120.

The P-GW 123 may further be a node for policy enforcement and chargingdata collection. Policy and Charging Enforcement Function (PCRF) 126 isthe policy and charging control element of the CN 120. In a non-roamingscenario, there may be a single PCRF in the Home Public Land MobileNetwork (HPLMN) associated with a UE's Internet Protocol ConnectivityAccess Network (IP-CAN) session. In a roaming scenario with localbreakout of traffic, there may be two PCRFs associated with a UE'sIP-CAN session: a Home PCRF (H-PCRF) within a HPLMN and a Visited PCRF(V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF126 may be communicatively coupled to the application server 130 via theP-GW 123. The application server 130 may signal the PCRF 126 to indicatea new service flow and select the appropriate Quality of Service (QoS)and charging parameters. The PCRF 126 may provision this rule into aPolicy and Charging Enforcement Function (PCEF) (not shown) with theappropriate traffic flow template (TFT) and QoS class of identifier(QCI), which commences the QoS and charging as specified by theapplication server 130.

The quantity of devices and/or networks illustrated in FIG. 1 isprovided for explanatory purposes only. In practice, there may beadditional devices and/or networks, fewer devices and/or networks,different devices and/or networks, or differently arranged devicesand/or networks than illustrated in FIG. 1 . Alternatively oradditionally, one or more of the devices of environment 100 may performone or more functions described as being performed by another one ormore of the devices of environment 100. Furthermore, while “direct”connections are shown in FIG. 1 , these connections should beinterpreted as logical communication pathways, and in practice, one ormore intervening devices (e.g., routers, gateways, modems, switches,hubs, etc.) may be present.

FIG. 2 illustrates an example for one or more BPLs between a UE and anaccess node in accordance with some embodiments of the disclosure. Inthe example of FIG. 2 , the AN 111 may maintain a plurality of transmit(Tx) beams including a Tx beam 210 and a Tx beam 211, and the UE 101 maymaintain a plurality of receive (Rx) beams including a Rx beam 220 and aRx beam 221. There may be one or more BPLs between the AN 111 and UE101, wherein each of the BPLs may be formed by a Tx beam of the AN 111and a Rx beam of the UE 101. For example, as shown in FIG. 2 , a BPL 230may be formed by the Tx beam 210 of the AN 111 and the Rx beam 220 ofthe UE 101, and a BPL 231 may be formed by the Tx beam 211 of the AN 111and the Rx beam 221 of the UE 101.

It should be understood that, the number of Tx beams of the AN 111, Rxbeams of the UE 101 and/or BPLs between the AN 111 and the UE 101illustrated in FIG. 2 is provided for explanatory purposes only and isnot limited herein.

FIG. 3 is a flow chart showing operations for configuration of a RS forbeam management in accordance with some embodiments of the disclosure.The operations of FIG. 3 may be used fora UE (e.g., UE 101) to recommenda configuration of a RS (such as an SS block or a CSI-RS) to an AN(e.g., AN 111) of a RAN (e.g., RAN 110) for beam management.

The AN 111 may process (e.g., modulate, encode, etc.) a plurality ofRSs, and transmit, at 305, the processed RSs to the UE 101 via aplurality of beams of the AN 111 for the plurality of RSs for use inradio link monitoring (RLM). In an embodiment, the plurality of RSs maybe transmitted with a beam sweeping operation. The plurality of RSs maybe a plurality of SS blocks or a plurality of CSI-RSs, which may bepredefined or configured by a higher layer signaling. In an embodiment,an SS block may include a Primary SS (PSS), a secondary SS (SSS) and aPhysical Broadcast Channel (PBCH). In an embodiment, an SS block mayalso include a Demodulation Reference Signal (DMRS) used for commoncontrol channel.

As discussed previously, it is possible to apply wide beams for SSblocks, and the AN 111 may configure some CSI-RS resources with narrowbeams on top of the best SS block(s). For example, as shown in FIG. 4A,wide beams (namely, SS block beams 410 and 411) are applied to SSblocks, and several narrow beams (namely, CSI-RS beams 420-423) areconfigured around or on top of the SS block beam 410 which is identifiedas a coarse transmission direction.

The UE 101 may receive the plurality of RSs that the AN 111 transmittedvia the plurality of beams at 305, and process (e.g., demodulate,decode, detect, etc.), at 310, the received RSs to determine first beamquality for each of a predefined subset of beams among the plurality ofbeams based on the processed RSs and to further determine second beamquality for the predefined subset of beams based on all of the firstbeam quality.

The AN 111 may configure a predefined subset of RS beams or resourcesamong all the plurality of RS beams or resources for beam measurement atthe UE 101, the number of beams or resources in the predefined subsetmay be N, and the number of all the beams or resources may be M, whereinN may be smaller than M. In an embodiment, M may indicate the number ofSS blocks in an SS block burst. The predefined subset of RS beams orresources may not cover all transmission directions associated with allthe plurality of RS beams or resources.

In an embodiment, the UE 101 may process (e.g., modulate, encode, etc.)an indicator for transmission to the AN 111, wherein the indicator mayindicate the maximum number of beams or resources (such as SS block orCSI-RS beams or resources) to be measured by the UE 101 in a frame or atiming window. That is to say, the indicator may indicate the processingcapability of the UE 101 to process beams or resources during a certaintime period. In an embodiment, the AN 111 may then determine orconfigure, based on the indicator received from the UE 101, the numberof beams in the predefined subset for beam measurement and management.

In an embodiment, for each of RSs associated with the one or more beamsnot within the predefined subset, a data channel or dedicated signal maybe transmitted in a slot for the RS. In an embodiment, for each of RSsassociated with the predefined subset of beams, no data channel ordedicated signal (such as a PDSCH) may be transmitted in a slot for theRS.

In an embodiment, the first beam quality for each of the predefinedsubset of beams may be determined by measuring a Signal to Interferenceplus Noise Ratio (SINR), a Reference Signal Receiving Power (RSRP) orReference Signal Receiving Quality (RSRQ) of the beam. The second beamquality may indicate overall beam quality for the predefined subset ofbeams. In an embodiment, the second beam quality may be an average ofall of the first beam quality.

In response to the second beam quality (namely, the overall beam qualityfor the predefined subset of beams) being below a predeterminedthreshold, the UE 101 may further determine, based on the processed RSs,third beam quality for each of one or more beams among the plurality ofbeams that are not within the predefined subset. In an embodiment, thethird beam quality for each of the one or more beams may be determinedby measuring a Signal to Interference plus Noise Ratio (SINR), aReference Signal Receiving Power (RSRP) or Reference Signal ReceivingQuality (RSRQ) of the beam. In an embodiment, the predeterminedthreshold may be predefined or configured by a higher layer signaling.

That is to say, the predefined subset of RS beams or resources may beviewed as a subset of all the plurality of RS beams or resources, andthe UE 101 may firstly perform beam measurement over the predefinedsubset of RS beams or resources so as to reduce the number of RS beamsor resources to be measured by the UE 101. If beam quality of beams inthe predefined subset does meet a threshold requirement (e.g., above thepredetermined threshold), the UE 101 may not need to perform beammeasurement over beams not within the predefined subset. However, ifbeam quality of beams in the predefined subset does not meet thethreshold requirement (e.g., below the predetermined threshold), the UE101 may need to perform beam measurement over beams not within thepredefined subset to find out one or more other beams not within thepredefined subset that have better beam quality.

At 315, the UE 101 may then process (e.g., modulate, encode, etc.),based on the first and third beam quality, a message for transmission tothe AN 111 for beam management, wherein the message identifies one ormore beam indexes for one or more SS blocks. In an embodiment, each ofthe beam indexes may be a timing index carried by a DemodulationReference Signal (DMRS) of a Physical Broadcast Channel (PBCH) of an SSblock associated with the beam index. In an embodiment, the message mayfurther identify beam quality for each of one or more beamscorresponding to the one or more beam indexes. In an embodiment, whetherthe UE 101 can process the message for transmission to the AN 111 or notmay be configured by a higher layer signaling or may be predefined.

In an embodiment, the message may further identify one or more flags forthe one or more beam indexes, and in the case that the plurality of RSsare a plurality of SS blocks, each of the flags may indicate one of:whether to recommend the AN 111 to add an SS beam corresponding to thebeam index associated with the flag into the predefined subset for beammeasurement; and whether to recommend the AN 111 to remove an SS beamcorresponding to the beam index associated with the flag from thepredefined subset.

In the case that the plurality of RSs are a plurality of SS blocks, asan example, FIG. 4B illustrates an example SS block configuration inaccordance with some embodiments of the disclosure. As shown in FIG. 4B,the AN 111 may transmit a plurality of SS blocks via a plurality of SSblock beams or resources 430-434. The AN 111 may configure a predefinedsubset of SS block beams or resources 432-434 (indicated with shadows inFIG. 4B) among all the plurality of SS block beams or resources 430-434for beam measurement at the UE 101. In this example, the number of SSblock beams or resources in the predefined subset may be 3, and thenumber of all the SS block beams or resources may be 5. As can be seen,the predefined subset of SS block beams or resources may not cover alltransmission directions associated with all the plurality of SS blockbeams or resources.

The UE 101 may firstly perform beam measurement over the predefinedsubset of SS block beams or resources 432-434 so as to reduce the numberof SS block beams or resources to be measured by the UE 101. If beamquality of beams in the predefined subset does meet a thresholdrequirement (e.g., above a first predetermined threshold T₁), the UE 101may not need to perform beam measurement over beams not within thepredefined subset. However, if beam quality of beams in the predefinedsubset does not meet the threshold requirement (e.g., below the firstpredetermined threshold T₁), the UE 101 may need to perform beammeasurement over beams not within the predefined subset to find out oneor more other beams not within the predefined subset that have betterbeam quality.

For example, if beam quality of beams in the predefined subset (namely,SS block beams or resources 432-434) does not meet the thresholdrequirement, the UE 101 may determine beam quality of SS block beams orresources 430-431. If the UE 101 determines that, for example, an SSblock beam 431 is a beam having better beam quality, the UE 101 mayprocess (e.g., modulate, encode, etc.) a message for transmission to theAN 111, wherein the message may identify a beam index of the SS blockbeam 431 to implicitly recommend the AN 111 to add the SS block beam orresource 431 corresponding to the beam index identified by the messagefor beam measurement. Alternatively, the message may further identify aflag for the beam index of the SS block beam 431, to explicitlyrecommend the AN 111 to add the SS block beam or resource 431corresponding to the beam index associated with the flag for beammeasurement. In addition, the message may further identify one or morebeam indexes of one or more SS block beams or resources within thepredefined subset that have bad beam quality, to implicitly recommendthe AN 111 to remove one or more SS block beams or resourcescorresponding to the one or more beam indexes identified by the message.For example, if beam quality of the SS block beam 434 is not goodenough, the message may identify a beam index of the SS block beam 434,to implicitly recommend the AN 111 to remove the SS block beam orresource 434 corresponding to the beam index identified by the message.Alternatively, the message may further identify a flag for the beamindex of the SS block beam 434, to explicitly recommend the AN 111 toremove the SS block beam or resource 434 corresponding to the beam indexassociated with the flag.

It should be understood that, the number of SS block beams and thenumber of beams in the predefined set illustrated in FIG. 4B areprovided for explanatory purposes only and are not limited herein.

In an embodiment, the message may further identify one or more flags forthe one or more beam indexes, and in the case that the plurality of RSsare a plurality of CSI-RSs, each of the flags may indicate one of:whether to recommend the AN 111 to add one or more CSI-RS beams into thepredefined subset based on the beam index associated with the flag forbeam measurement; and whether to recommend the AN 111 to remove one ormore CSI-RS beams from the predefined subset based on the beam indexassociated with the flag.

In the case that the plurality of RSs are a plurality of CSI-RSs, as anexample, FIG. 4C illustrates an example CSI-RS configuration inaccordance with some embodiments of the disclosure. As shown in FIG. 4C,the AN 111 may transmit a plurality of CSI-RSs via a plurality of CSI-RSbeams or resources 450-457, wherein CSI-RS beams or resources 450-453are configured around or on top of an SS block beam 440, and CSI-RSbeams or resources 454-457 are configured around or on top of an SSblock beam 441. The AN 111 may configure a predefined subset of CSI-RSbeams or resources 450-453 (indicated with shadows in FIG. 4C) among allthe plurality of CSI-RS beams or resources 450-457 for beam measurementat the UE 101. In this example, the number of CSI-RS beams or resourcesin the predefined subset may be 4, and the number of all the CSI-RSbeams or resources may be 8. As can be seen, the predefined subset ofCSI-RS beams or resources may not cover all transmission directionsassociated with all the plurality of CSI-RS beams or resources.

The UE 101 may firstly perform beam measurement over the predefinedsubset of CSI-RS beams or resources 450-453 so as to reduce the numberof CSI-RS beams or resources to be measured by the UE 101. If beamquality of beams in the predefined subset does meet a thresholdrequirement (e.g., above a second predetermined threshold T₂), the UE101 may not need to perform beam measurement over beams not within thepredefined subset. However, if beam quality of beams in the predefinedsubset does not meet the threshold requirement (e.g., below the secondpredetermined threshold T₂), the UE 101 may need to perform beammeasurement over beams not within the predefined subset to find out oneor more other beams not within the predefined subset that have betterbeam quality.

For example, if beam quality of beams in the predefined subset (namely,CSI-RS beams or resources 450-453) does not meet the thresholdrequirement, the UE 101 may determine beam quality of CSI-RS beams orresources 454-457. If the UE 101 determines that, for example, one ormore of CSI-RS beams or resources 454-457 have better beam quality, theUE 101 may process (e.g., modulate, encode, etc.) a message fortransmission to the AN 111, wherein the message may identify a beamindex of the SS block beam 441 associated with the CSI-RS beams orresources 454-457, to implicitly recommend the AN 111 to update a CSI-RSconfiguration to add some CSI-RS beams or resources around or on top ofthe SS block beam 441 corresponding to the beam index identified by themessage for beam measurement. Alternatively, the message may furtheridentify a flag for the beam index of the SS block beam 441, toexplicitly recommend the AN 111 to add some CSI-RS beams or resourcesaround or on top of the SS block beam 441 corresponding to the beamindex associated with the flag for beam measurement. In addition, themessage may further identify one or more beam indexes of one or more SSblock beams or resources associated with one or more CSI-RS beams orresources within the predefined subset that have bad beam quality, toimplicitly recommend the AN 111 to update a CSI-RS configuration toremove one or more CSI-RS beams or resources around or on top of the oneor more SS block beams or resources associated with the one or more beamindexes identified by the message. For example, if beam quality of theCSI-RS block beams 450-453 are not good enough, the message may identifya beam index of the SS block beam 440 associated with the CSI-RS beamsor resources 450-453, to implicitly recommend the AN 111 to update aCSI-RS configuration to remove one or more CSI-RS beams or resourcesaround or on top of the SS block beam or resource 440 associated withthe beam index identified by the message. Alternatively, the message mayfurther identify a flag for the beam index of the SS block beam 440, toexplicitly recommend the AN 111 to update a CSI-RS configuration toremove one or more CSI-RS beams or resources around or on top of the SSblock beam or resource 440 corresponding to the beam index associatedwith the flag.

It should be understood that, the number of SS block beams, the numberof CSI-RS beams, and the number of beams in the predefined setillustrated in FIG. 4C are provided for explanatory purposes only andare not limited herein.

At 320, the UE 101 may transmit the message processed at 315 to the AN111. In an embodiment, the message may be transmitted via a PhysicalUplink Control Channel (PUCCH), a Medium Access Control (MAC) ControlElement (CE), or a Radio Resource Control (RRC) signaling.

The AN 111 may receive the message transmitted at 320 by the UE 101, andprocess (e.g., demodulate, decode, detect, etc.), at 325, the receivedmessage to update a RS configuration to add or remove one or more beamsbased on the one or more beam indexes identified by the message.

FIG. 5 is a flow chart showing a method performed by a UE forconfiguration of a RS for beam management in accordance with someembodiments of the disclosure. The operations of FIG. 5 may be used fora UE (e.g., UE 101) to recommend a configuration of a RS (such as an SSblock or a CSI-RS) to an AN (e.g., AN 111) of a RAN (e.g., RAN 110) forbeam management.

The method starts at 505. At 510, the UE 101 may process (e.g.,demodulate, decode, detect, etc.) a plurality of RSs received from theAN 111 via a plurality of beams of the AN 111 for the plurality of RSs.At 515, the UE 101 may determine, based on the processed RSs, first beamquality for each of a predefined subset of beams among the plurality ofbeams. At 520, the UE 101 may determine second beam quality for thepredefined subset of beams based on all of the first beam quality. Asdiscussed previously with reference to FIG. 3 in detail, beam quality ofone beam may be determined by measuring a SINR, a RSRP or RSRQ of thebeam.

Then, the UE 101 may determine whether the second beam quality for thepredefined subset of beams meets a threshold requirement (e.g., above apredetermined threshold) at 525. If yes, the method may return back to510, and if not, the method may proceed to 530, where the UE 101 maydetermine, based on the processed RSs, third beam quality for each ofone or more beams among the plurality of beams that are not within thepredefined subset.

At 535, the UE 101 may then process (e.g., modulate, encode, etc.),based on the first and third beam quality, a message for transmission tothe AN 111 for beam management, wherein the message identifies one ormore beam indexes for one or more SS blocks. At 540, the UE 101 maytransmit the message to the AN 111.

For the sake of brevity, some embodiments which have already beendescribed in detail with reference to FIG. 3 and FIGS. 4A-4C will not berepeated herein. The method ends at 545.

FIG. 6 is a flow chart showing operations for configuration of a TRS fortime and/or frequency offset tracking in accordance with someembodiments of the disclosure. The operations of FIG. 6 may be used fora UE (e.g., UE 101) to process a TRS received from an AN (e.g., AN 111)of a RAN (e.g., RAN 110) for time and/or frequency offset tracking.

Optionally, the UE 101 may process (e.g., modulate, encode, etc.) arequest for a TRS, and transmit, at 605, the processed request to the AN111 to trigger the AN 111 to process and transmit a TRS to the UE 101.In an embodiment, the processed request may be transmitted at 605 via aPUCCH, a PRACH, or a higher layer signaling.

In response to receiving the request transmitted at 605 from the UE 101,the AN 111 may determine at 610, a time density of a TRS based on asubcarrier spacing of a bandwidth part (BWP) in a current componentcarrier for the UE 101, a frequency density of the TRS based on abandwidth of the TRS, and a quasi co-location (QCL) relationship of theTRS. Then at 615, the AN 111 may process (e.g., modulate, encode,determine, etc.) the TRS, based on at least one of the time density, thefrequency density and the QCL relationship determined at 610, fortransmission to the UE 101. It is to be noted that, it is optional forthe UE 101 to process and transmit at 605 the request for a TRS, and itis not necessary for the AN 111 to process the TRS at 615 based on thetime density, frequency density and QCL relationship of the TRSdetermined at 610 only in response to receiving a request for the TRSfrom the UE 101. In an embodiment, the AN 111 may also process the TRSat 615 based on the time density, frequency density and QCL relationshipof the TRS determined at 610 in response to a higher layer signaling ora Downlink Control Information (DCI) or a combination thereof.

A TRS pattern should provide enough time and/or frequency offsettracking accuracy which may rely on a time density and a frequencydensity of the TRS pattern. For accurate Doppler offset estimation, theduration of one TRS instance (namely, the duration of one or more slotscarrying the TRS instance) should be long enough. For example, a TRS maybe mapped to 2 slots. However, since a subcarrier spacing of a BWP mayvary, the duration of one slot may vary. Therefore, the number of slotsfor a TRS may vary, and may be determined based on a subcarrier spacingof a BWP. Alternatively, the number of slots for the TRS may bedetermined by a higher layer signaling or a DCI or a combinationthereof. For example, in a 5G NR system, currently the number of slotsfor a TRS instance may be configured by a RRC signaling with a valueselected from candidate values {1, 2}. In an embodiment, the timedensity of the TRS processed at 610 may indicate the number M of slotsfor the TRS. Table 1 as shown below illustrates an example of anassociation between the number of slots for a TRS instance (namely, thetime density of a TRS) and a subcarrier spacing of a BWP for a UE. Theassociation in Table 1 may be predefined or configured by a higher layersignaling.

TABLE 1 an example of an association between the number of slots for aTRS and a subcarrier spacing The number of slots for Subcarrier spacinga TRS instance (M)   15 kHz 1 30 kHz, 60 kHz 2 >=120 kHz 4

The total number of symbols for a TRS instance may be fixed or may beconfigured by a higher layer signaling. For example, in a 5G NR system,currently the number of symbols for a TRS per slot may be fixed to be 2.One or more symbol indexes for the TRS may be different for differentsubcarrier spacing. As an example, the number of symbols for a TRSinstance may be fixed to 4, and if the TRS occupies 4 slots for example,then each symbol for the TRS may be mapped to each slot for the TRS,that is to say, the TRS may occupy one symbol per slot. In this example,the TRS may be evenly distributed in time domain. In addition, the TRSmay not be mapped to a control Resource Set (COREST) for a UE. Then whena collision occurs, the collided symbol for the TRS may be shifted, orthe whole TRS may be shifted, or the TRS may not be transmitted on thecollided resource. Further, the same or different comb offset (which mayindicate a subcarrier offset, and may indicate a location of a firstResource Element (RE) for the TRS in frequency domain) may be applied todifferent symbols, which may be predefined or configured by a higherlayer signaling.

The channel estimation accuracy may rely on the frequency density of theTRS. In an embodiment, the frequency density may indicate the number Nof subcarriers carrying the TRS in a symbol of a Physical Resource Block(PRB). As discussed previously, the AN 111 may determine the frequencydensity of the TRS based on the bandwidth of the TRS. In an embodiment,the bandwidth of the TRS may be determined based on at least one of: abandwidth of the BWP, and the subcarrier spacing of the BWP. In anexample, the bandwidth of the TRS may not be smaller than 24 RB, and maynot be larger than min{50, Q} RB, where Q is the number of PRBs in theBWP. In another example, the bandwidth of the TRS may be the minimum of52 and the number Q of PRBs in the BWP, or may be equal to the number Qof PRBs in the BWP. Alternatively, in another embodiment, the frequencydensity of the TRS may be fixed. Further, in yet another embodiment, thefrequency density of the TRS may also be determined by the subcarrierspacing. Table 2 as shown below illustrates an example of an associationbetween a bandwidth of a TRS and a frequency density of the TRS, whereinthe subcarrier spacing is 30 KHz. The association in Table 2 may bepredefined or configured by a higher layer signaling.

TABLE 2 an example of an association between a bandwidth of a TRS and afrequency density of the TRS Frequency Bandwidth for TRS density of TRSB <= 24 RB 3 RE/RB/Symbol 24 RB < B <= 50 RB 2 RE/RB/Symbol B > 50 RB 1RE/RB/Symbol

FIG. 7A illustrates an example of a TRS pattern, wherein the number ofslots for a TRS is 1, namely, M=1. Each resource element (RE) occupiedby the TRS may be indicated with shadows, wherein one RE consists of asymbol in time domain and a subcarrier in frequency domain. As can beseen, the TRS occupies one slot which contains fourteen symbols in timedomain (namely, the time density of the TRS is equal to 1), and foursymbols among all the fourteen symbols are occupied by the TRS. Inaddition, in frequency domain, the TRS occupies three subcarriers amongall the twelve subcarriers in each symbol occupied by the TRS of one PRB(which comprises fourteen symbols in time domain and twelve subcarriersin frequency domain) shown in FIG. 7A, that is to say, the frequencydensity of the TRS is equal to 3.

In addition, to support a multi-beam operation, multiple TRS resourcesmay be configured. Within each TRS resource, information regarding theQCL relationship may be configured. In an embodiment, the QCLrelationship of the TRS may be predefined or configured by a higherlayer signaling. In an embodiment, the QCL relationship may indicatethat the TRS is QCLed with an SS block or a CSI-RS for beam management,and thus a timing index of the SS block or a CSI-RS Resource Index (CRI)of the CSI-RS may be used to indicate a beam of the TRS. In anembodiment, the SS block or the CSI-RS may be within the BWP in thecurrent component carrier. In another embodiment, the SS block or theCSI-RS may be within another BWP in the current component carrier oranother component carrier, which is different from the BWP in thecomponent carrier for the TRS. In an embodiment, the TRS may betransmitted in M−1 consecutive slots before or after the SS block or theCSI-RS QCLed with the TRS, wherein M may indicate the number of slotsfor the TRS (for example, may be determined with reference to Table 1),and related contents have already been described in detail previouslyand thus will not be repeated herein. In an embodiment, whether an SSblock or a CSI-RS is configured to be QCLed with the TRS may bedetermined by a Layer 1 Reference Signal Receiving Power (L1-RSRP)reporting mode, which may indicate one of: a L1-RSRP reporting is basedon a CSI-RS only, a L1-RSRP reporting is based on an SS block only, anda L1-RSRP reporting is based on both of a CSI-RS and an SS block.

In addition, different TRS resources may be multiplexed in a TimeDivision Multiplexing (TDM) manner and/or a Frequency DivisionMultiplexing (FDM) manner. FIG. 7B illustrates an example formultiplexing of different TRS resources (indicated with two differentshadows of two different directions) in a FDM manner, and FIG. 7Cillustrates an example for multiplexing of different TRS resources(indicated with two different shadows of two different directions) in aTDM manner. For the TDM manner, different TRS resources may also betransmitted in different slots.

A cross-carrier and cross-BWP QCL relationship between a TRS and a DMRSand/or a CSI-RS or an SS-block may be pre-defined or configured byhigher layer signaling. In an example, for a BWP or component carrierwithout a TRS, time and/or frequency offset tracking may be performedbased on a configured TRS from another BWP or component carrier. In anembodiment, the TRS may be a CSI-RS.

At 620, the AN 111 may transmit the TRS processed at 615 to the UE 101.In an embodiment, the TRS may be transmitted in a manner selected from aperiodic manner, an aperiodic manner, and a semi-persistent manner.

The UE 101 may receive the TRS transmitted at 620 by the AN 111, andprocess (e.g., demodulate, decode, detect, etc.), at 625, the receivedTRS to estimate the time and/or frequency offset. In an embodiment, theUE 101 may estimate the time and/or frequency offset based on the TRSand the SS block or CSI-RS QCLed with the TRS.

In addition, in an embodiment, a gap period for decoding a TRS may bedetermined, so as to support a multi-TRP operation. The gap period mayenable the UE 101 to switch, from measuring a time and/or frequencyoffset of the AN 111, to measure a time and/or frequency offset ofanother access node (such as the AN 112 shown in FIG. 1 ). In anembodiment, the gap period may be configured by a higher layersignaling. In an embodiment, the UE 101 may process (e.g., demodulate,decode, detect, etc.) another TRS received from another access node(such as the AN 112) during the gap period, wherein during the gapperiod, no data will be transmitted from the AN 111 to the UE 101, andthus the UE 101 will not receive any data from the AN 111.

FIG. 8 is a flow chart showing a method performed by an access node forconfiguration of a TRS for time and/or frequency offset tracking inaccordance with some embodiments of the disclosure. The operations ofFIG. 8 may be used for an AN (e.g., AN 111) of a RAN (e.g., RAN 110) toprocess a TRS for transmission to a UE (e.g., UE 101) for time and/orfrequency offset tracking.

The method starts at 805. At 810-820, the AN 111 may determine a timedensity of a TRS based on a subcarrier spacing of a BWP in a currentcomponent carrier for the UE 101, a frequency density of the TRS basedon a bandwidth of the TRS, and a QCL relationship of the TRSrespectively. Then at 825, the AN 111 may process (e.g., modulate,encode, determine, etc.) the TRS, based on at least one of the timedensity, the frequency density and the QCL relationship determined at810-820, for transmission to the UE 101. At 830, the AN 111 may transmitthe TRS processed at 825 to the UE 101 for time and/or frequency offsettracking.

For the sake of brevity, some embodiments which have already beendescribed in detail with reference to FIG. 6 and FIGS. 7A-7C will not berepeated herein. The method ends at 835.

FIG. 9 is a flow chart showing a method performed by a UE forconfiguration of a TRS for time and/or frequency offset in accordancewith some embodiments of the disclosure. The operations of FIG. 9 may beused for a multi-TRP operation to enable a UE (e.g., UE 101) to processdifferent TRSs received from different ANs (e.g., AN 111 and AN 112) ofa RAN (e.g., RAN 110) for time and/or frequency offset tracking.

The method starts at 905. At 910, The UE 101 may process (e.g.,demodulate, decode, detect, etc.) a first TRS received from a firstaccess node (such as the AN 111) to measure a time and/or frequencyoffset of the AN 111. At 915, The UE 101 may determine a gap period. Thegap period may enable the UE 101 to switch, from measuring a time and/orfrequency offset of the AN 111, to measure a time and/or frequencyoffset of a second access node (such as the AN 112). At 920, The UE 101may process (e.g., demodulate, decode, detect, etc.) a second TRSreceived from a second access node (such as the AN 112) to measure atime and/or frequency offset of the AN 112. During the gap period, nodata will be transmitted from the AN 111 to the UE 101, and thus the UE101 will not receive any data from the AN 111.

For the sake of brevity, some embodiments which have already beendescribed in detail with reference to FIG. 6 and FIGS. 7A-7C will not berepeated herein. The method ends at 925.

FIG. 10 illustrates example components of a device 1000 in accordancewith some embodiments. In some embodiments, the device 1000 may includeapplication circuitry 1002, baseband circuitry 1004, Radio Frequency(RF) circuitry 1006, front-end module (FEM) circuitry 1008, one or moreantennas 1010, and power management circuitry (PMC) 1012 coupledtogether at least as shown. The components of the illustrated device1000 may be included in a UE or an AN. In some embodiments, the device1000 may include less elements (e.g., an AN may not utilize applicationcircuitry 1002, and instead include a processor/controller to process IPdata received from an EPC). In some embodiments, the device 1000 mayinclude additional elements such as, for example, memory/storage,display, camera, sensor, or input/output (I/O) interface. In otherembodiments, the components described below may be included in more thanone device (e.g., said circuitries may be separately included in morethan one device for Cloud-RAN (C-RAN) implementations).

The application circuitry 1002 may include one or more applicationprocessors. For example, the application circuitry 1002 may includecircuitry such as, but not limited to, one or more single-core ormulti-core processors. The processor(s) may include any combination ofgeneral-purpose processors and dedicated processors (e.g., graphicsprocessors, application processors, etc.). The processors may be coupledwith or may include memory/storage and may be configured to executeinstructions stored in the memory/storage to enable various applicationsor operating systems to run on the device 1000. In some embodiments,processors of application circuitry 1002 may process IP data packetsreceived from an EPC.

The baseband circuitry 1004 may include circuitry such as, but notlimited to, one or more single-core or multi-core processors. Thebaseband circuitry 1004 may include one or more baseband processors orcontrol logic to process baseband signals received from a receive signalpath of the RF circuitry 1006 and to generate baseband signals for atransmit signal path of the RF circuitry 1006. Baseband processingcircuitry 1004 may interface with the application circuitry 1002 forgeneration and processing of the baseband signals and for controllingoperations of the RF circuitry 1006. For example, in some embodiments,the baseband circuitry 1004 may include a third generation (3G) basebandprocessor 1004A, a fourth generation (4G) baseband processor 1004B, afifth generation (5G) baseband processor 1004C, or other basebandprocessor(s) 1004D for other existing generations, generations indevelopment or to be developed in the future (e.g., second generation(2G), sixth generation (6G), etc.). The baseband circuitry 1004 (e.g.,one or more of baseband processors 1004A-D) may handle various radiocontrol functions that enable communication with one or more radionetworks via the RF circuitry 1006. In other embodiments, some or all ofthe functionality of baseband processors 1004A-D may be included inmodules stored in the memory 1004G and executed via a Central ProcessingUnit (CPU) 1004E. The radio control functions may include, but are notlimited to, signal modulation/demodulation, encoding/decoding, radiofrequency shifting, etc. In some embodiments, modulation/demodulationcircuitry of the baseband circuitry 1004 may include Fast-FourierTransform (FFT), precoding, or constellation mapping/demappingfunctionality. In some embodiments, encoding/decoding circuitry of thebaseband circuitry 1004 may include convolution, tail-bitingconvolution, turbo, Viterbi, or Low Density Parity Check (LDPC)encoder/decoder functionality. Embodiments of modulation/demodulationand encoder/decoder functionality are not limited to these examples andmay include other suitable functionality in other embodiments.

In some embodiments, the baseband circuitry 1004 may include one or moreaudio digital signal processor(s) (DSP) 1004F. The audio DSP(s) 1004Fmay include elements for compression/decompression and echo cancellationand may include other suitable processing elements in other embodiments.Components of the baseband circuitry may be suitably combined in asingle chip, a single chipset, or disposed on a same circuit board insome embodiments. In some embodiments, some or all of the constituentcomponents of the baseband circuitry 1004 and the application circuitry1002 may be implemented together such as, for example, on a system on achip (SOC).

In some embodiments, the baseband circuitry 1004 may provide forcommunication compatible with one or more radio technologies. Forexample, in some embodiments, the baseband circuitry 1004 may supportcommunication with an evolved universal terrestrial radio access network(EUTRAN) or other wireless metropolitan area networks (WMAN), a wirelesslocal area network (WLAN), a wireless personal area network (WPAN).Embodiments in which the baseband circuitry 1004 is configured tosupport radio communications of more than one wireless protocol may bereferred to as multi-mode baseband circuitry.

RF circuitry 1006 may enable communication with wireless networks usingmodulated electromagnetic radiation through a non-solid medium. Invarious embodiments, the RF circuitry 1006 may include switches,filters, amplifiers, etc. to facilitate the communication with thewireless network. RF circuitry 1006 may include a receive signal pathwhich may include circuitry to down-convert RF signals received from theFEM circuitry 1008 and provide baseband signals to the basebandcircuitry 1004. RF circuitry 1006 may also include a transmit signalpath which may include circuitry to up-convert baseband signals providedby the baseband circuitry 1004 and provide RF output signals to the FEMcircuitry 1008 for transmission.

In some embodiments, the receive signal path of the RF circuitry 1006may include mixer circuitry 1006 a, amplifier circuitry 1006 b andfilter circuitry 1006 c. In some embodiments, the transmit signal pathof the RF circuitry 1006 may include filter circuitry 1006 c and mixercircuitry 1006 a. RF circuitry 1006 may also include synthesizercircuitry 1006 d for synthesizing a frequency for use by the mixercircuitry 1006 a of the receive signal path and the transmit signalpath. In some embodiments, the mixer circuitry 1006 a of the receivesignal path may be configured to down-convert RF signals received fromthe FEM circuitry 1008 based on the synthesized frequency provided bysynthesizer circuitry 1006 d. The amplifier circuitry 1006 b may beconfigured to amplify the down-converted signals and the filtercircuitry 1006 c may be a low-pass filter (LPF) or band-pass filter(BPF) configured to remove unwanted signals from the down-convertedsignals to generate output baseband signals. Output baseband signals maybe provided to the baseband circuitry 1004 for further processing. Insome embodiments, the output baseband signals may be zero-frequencybaseband signals, although this is not a requirement. In someembodiments, mixer circuitry 1006 a of the receive signal path maycomprise passive mixers, although the scope of the embodiments is notlimited in this respect.

In some embodiments, the mixer circuitry 1006 a of the transmit signalpath may be configured to up-convert input baseband signals based on thesynthesized frequency provided by the synthesizer circuitry 1006 d togenerate RF output signals for the FEM circuitry 1008. The basebandsignals may be provided by the baseband circuitry 1004 and may befiltered by filter circuitry 1006 c.

In some embodiments, the mixer circuitry 1006 a of the receive signalpath and the mixer circuitry 1006 a of the transmit signal path mayinclude two or more mixers and may be arranged for quadraturedownconversion and upconversion, respectively. In some embodiments, themixer circuitry 1006 a of the receive signal path and the mixercircuitry 1006 a of the transmit signal path may include two or moremixers and may be arranged for image rejection (e.g., Hartley imagerejection). In some embodiments, the mixer circuitry 1006 a of thereceive signal path and the mixer circuitry 1006 a may be arranged fordirect downconversion and direct upconversion, respectively. In someembodiments, the mixer circuitry 1006 a of the receive signal path andthe mixer circuitry 1006 a of the transmit signal path may be configuredfor super-heterodyne operation.

In some embodiments, the output baseband signals and the input basebandsignals may be analog baseband signals, although the scope of theembodiments is not limited in this respect. In some alternateembodiments, the output baseband signals and the input baseband signalsmay be digital baseband signals. In these alternate embodiments, the RFcircuitry 1006 may include analog-to-digital converter (ADC) anddigital-to-analog converter (DAC) circuitry and the baseband circuitry1004 may include a digital baseband interface to communicate with the RFcircuitry 1006.

In some dual-mode embodiments, a separate radio IC circuitry may beprovided for processing signals for each spectrum, although the scope ofthe embodiments is not limited in this respect.

In some embodiments, the synthesizer circuitry 1006 d may be afractional-N synthesizer or a fractional N/N+1 synthesizer, although thescope of the embodiments is not limited in this respect as other typesof frequency synthesizers may be suitable. For example, synthesizercircuitry 1006 d may be a delta-sigma synthesizer, a frequencymultiplier, or a synthesizer comprising a phase-locked loop with afrequency divider.

The synthesizer circuitry 1006 d may be configured to synthesize anoutput frequency for use by the mixer circuitry 1006 a of the RFcircuitry 1006 based on a frequency input and a divider control input.In some embodiments, the synthesizer circuitry 1006 d may be afractional N/N+1 synthesizer.

In some embodiments, frequency input may be provided by a voltagecontrolled oscillator (VCO), although that is not a requirement. Dividercontrol input may be provided by either the baseband circuitry 1004 orthe applications processor 1002 depending on the desired outputfrequency. In some embodiments, a divider control input (e.g., N) may bedetermined from a look-up table based on a channel indicated by theapplications processor 1002.

Synthesizer circuitry 1006 d of the RF circuitry 1006 may include adivider, a delay-locked loop (DLL), a multiplexer and a phaseaccumulator. In some embodiments, the divider may be a dual modulusdivider (DMD) and the phase accumulator may be a digital phaseaccumulator (DPA). In some embodiments, the DMD may be configured todivide the input signal by either N or N+1 (e.g., based on a carry out)to provide a fractional division ratio. In some example embodiments, theDLL may include a set of cascaded, tunable, delay elements, a phasedetector, a charge pump and a D-type flip-flop. In these embodiments,the delay elements may be configured to break a VCO period up into Ndequal packets of phase, where Nd is the number of delay elements in thedelay line. In this way, the DLL provides negative feedback to helpensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuitry 1006 d may be configured togenerate a carrier frequency as the output frequency, while in otherembodiments, the output frequency may be a multiple of the carrierfrequency (e.g., twice the carrier frequency, four times the carrierfrequency) and used in conjunction with quadrature generator and dividercircuitry to generate multiple signals at the carrier frequency withmultiple different phases with respect to each other. In someembodiments, the output frequency may be a LO frequency (fLO). In someembodiments, the RF circuitry 1006 may include an IQ/polar converter.

FEM circuitry 1008 may include a receive signal path which may includecircuitry configured to operate on RF signals received from one or moreantennas 1010, amplify the received signals and provide the amplifiedversions of the received signals to the RF circuitry 1006 for furtherprocessing. FEM circuitry 1008 may also include a transmit signal pathwhich may include circuitry configured to amplify signals fortransmission provided by the RF circuitry 1006 for transmission by oneor more of the one or more antennas 1010. In various embodiments, theamplification through the transmit or receive signal paths may be donesolely in the RF circuitry 1006, solely in the FEM 1008, or in both theRF circuitry 1006 and the FEM 1008.

In some embodiments, the FEM circuitry 1008 may include a TX/RX switchto switch between transmit mode and receive mode operation. The FEMcircuitry may include a receive signal path and a transmit signal path.The receive signal path of the FEM circuitry may include an LNA toamplify received RF signals and provide the amplified received RFsignals as an output (e.g., to the RF circuitry 1006). The transmitsignal path of the FEM circuitry 1008 may include a power amplifier (PA)to amplify input RF signals (e.g., provided by RF circuitry 1006), andone or more filters to generate RF signals for subsequent transmission(e.g., by one or more of the one or more antennas 1010).

In some embodiments, the PMC 1012 may manage power provided to thebaseband circuitry 1004. In particular, the PMC 1012 may controlpower-source selection, voltage scaling, battery charging, or DC-to-DCconversion. The PMC 1012 may often be included when the device 1000 iscapable of being powered by a battery, for example, when the device isincluded in a UE. The PMC 1012 may increase the power conversionefficiency while providing desirable implementation size and heatdissipation characteristics.

While FIG. 10 shows the PMC 1012 coupled only with the basebandcircuitry 1004. However, in other embodiments, the PMC 1012 may beadditionally or alternatively coupled with, and perform similar powermanagement operations for, other components such as, but not limited to,application circuitry 1002, RF circuitry 1006, or FEM 1008.

In some embodiments, the PMC 1012 may control, or otherwise be part of,various power saving mechanisms of the device 1000. For example, if thedevice 1000 is in an RRC_Connected state, where it is still connected tothe AN as it expects to receive traffic shortly, then it may enter astate known as Discontinuous Reception Mode (DRX) after a period ofinactivity. During this state, the device 1000 may power down for briefintervals of time and thus save power.

If there is no data traffic activity for an extended period of time,then the device 1000 may transition off to an RRC_Idle state, where itdisconnects from the network and does not perform operations such aschannel quality feedback, handover, etc. The device 1000 goes into avery low power state and it performs paging where again it periodicallywakes up to listen to the network and then powers down again. The device1000 may not receive data in this state, in order to receive data, itmust transition back to RRC_Connected state.

An additional power saving mode may allow a device to be unavailable tothe network for periods longer than a paging interval (ranging fromseconds to a few hours). During this time, the device is totallyunreachable to the network and may power down completely. Any data sentduring this time incurs a large delay and it is assumed the delay isacceptable.

Processors of the application circuitry 1002 and processors of thebaseband circuitry 1004 may be used to execute elements of one or moreinstances of a protocol stack. For example, processors of the basebandcircuitry 1004, alone or in combination, may be used execute Layer 3,Layer 2, or Layer 1 functionality, while processors of the applicationcircuitry 1004 may utilize data (e.g., packet data) received from theselayers and further execute Layer 4 functionality (e.g., transmissioncommunication protocol (TCP) and user datagram protocol (UDP) layers).As referred to herein, Layer 3 may comprise a radio resource control(RRC) layer. As referred to herein, Layer 2 may comprise a medium accesscontrol (MAC) layer, a radio link control (RLC) layer, and a packet dataconvergence protocol (PDCP) layer, Layer 1 may comprise a physical (PHY)layer of a UE/AN.

FIG. 11 illustrates example interfaces of baseband circuitry inaccordance with some embodiments. As discussed above, the basebandcircuitry 1004 of FIG. 10 may comprise processors 1004A-1004E and amemory 1004G utilized by said processors. Each of the processors1004A-1004E may include a memory interface, 1104A-1104E, respectively,to send/receive data to/from the memory 1004G.

The baseband circuitry 1004 may further include one or more interfacesto communicatively couple to other circuitries/devices, such as a memoryinterface 1112 (e.g., an interface to send/receive data to/from memoryexternal to the baseband circuitry 1004), an application circuitryinterface 1114 (e.g., an interface to send/receive data to/from theapplication circuitry 1002 of FIG. 10 ), an RF circuitry interface 1116(e.g., an interface to send/receive data to/from RF circuitry 1006 ofFIG. 10 ), a wireless hardware connectivity interface 1118 (e.g., aninterface to send/receive data to/from Near Field Communication (NFC)components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi®components, and other communication components), and a power managementinterface 1120 (e.g., an interface to send/receive power or controlsignals to/from the PMC 1012.

FIG. 12 is an illustration of a control plane protocol stack inaccordance with some embodiments. In this embodiment, a control plane1200 is shown as a communications protocol stack between the UE 101, theAN 111 (or alternatively, the AN 112), and the MME 121.

The PHY layer 1201 may transmit or receive information used by the MAClayer 1202 over one or more air interfaces. The PHY layer 1201 mayfurther perform link adaptation or adaptive modulation and coding (AMC),power control, cell search (e.g., for initial synchronization andhandover purposes), and other measurements used by higher layers, suchas the RRC layer 1205. The PHY layer 1201 may still further performerror detection on the transport channels, forward error correction(FEC) coding/decoding of the transport channels, modulation/demodulationof physical channels, interleaving, rate matching, mapping onto physicalchannels, and Multiple Input Multiple Output (MIMO) antenna processing.

The MAC layer 1202 may perform mapping between logical channels andtransport channels, multiplexing of MAC service data units (SDUs) fromone or more logical channels onto transport blocks (TB) to be deliveredto PHY via transport channels, de-multiplexing MAC SDUs to one or morelogical channels from transport blocks (TB) delivered from the PHY viatransport channels, multiplexing MAC SDUs onto TBs, schedulinginformation reporting, error correction through hybrid automatic repeatrequest (HARQ), and logical channel prioritization.

The RLC layer 1203 may operate in a plurality of modes of operation,including: Transparent Mode (TM), Unacknowledged Mode (UM), andAcknowledged Mode (AM). The RLC layer 1203 may execute transfer of upperlayer protocol data units (PDUs), error correction through automaticrepeat request (ARQ) for AM data transfers, and concatenation,segmentation and reassembly of RLC SDUs for UM and AM data transfers.The RLC layer 1203 may also execute re-segmentation of RLC data PDUs forAM data transfers, reorder RLC data PDUs for UM and AM data transfers,detect duplicate data for UM and AM data transfers, discard RLC SDUs forUM and AM data transfers, detect protocol errors for AM data transfers,and perform RLC re-establishment.

The PDCP layer 1204 may execute header compression and decompression ofIP data, maintain PDCP Sequence Numbers (SNs), perform in-sequencedelivery of upper layer PDUs at re-establishment of lower layers,eliminate duplicates of lower layer SDUs at re-establishment of lowerlayers for radio bearers mapped on RLC AM, cipher and decipher controlplane data, perform integrity protection and integrity verification ofcontrol plane data, control timer-based discard of data, and performsecurity operations (e.g., ciphering, deciphering, integrity protection,integrity verification, etc.).

The main services and functions of the RRC layer 1205 may includebroadcast of system information (e.g., included in Master InformationBlocks (MIBs) or System Information Blocks (SIBs) related to thenon-access stratum (NAS)), broadcast of system information related tothe access stratum (AS), paging, establishment, maintenance and releaseof an RRC connection between the UE and E-UTRAN (e.g., RRC connectionpaging, RRC connection establishment, RRC connection modification, andRRC connection release), establishment, configuration, maintenance andrelease of point to point Radio Bearers, security functions includingkey management, inter radio access technology (RAT) mobility, andmeasurement configuration for UE measurement reporting. Said MIBs andSIBs may comprise one or more information elements (IEs), which may eachcomprise individual data fields or data structures.

The UE 101 and the AN 111 may utilize a Uu interface (e.g., an LTE-Uuinterface) to exchange control plane data via a protocol stackcomprising the PHY layer 1201, the MAC layer 1202, the RLC layer 1203,the PDCP layer 1204, and the RRC layer 1205.

The non-access stratum (NAS) protocols 1206 form the highest stratum ofthe control plane between the UE 101 and the MME 121. The NAS protocols1206 support the mobility of the UE 101 and the session managementprocedures to establish and maintain IP connectivity between the UE 101and the P-GW 123.

The S1 Application Protocol (S1-AP) layer 1215 may support the functionsof the S1 interface and comprise Elementary Procedures (EPs). An EP is aunit of interaction between the AN 111 and the CN 120. The S1-AP layerservices may comprise two groups: UE-associated services and nonUE-associated services. These services perform functions including, butnot limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UEcapability indication, mobility, NAS signaling transport, RANInformation Management (RIM), and configuration transfer.

The Stream Control Transmission Protocol (SCTP) layer (alternativelyreferred to as the SCTP/IP layer) 1214 may ensure reliable delivery ofsignaling messages between the AN 111 and the MME 121 based, in part, onthe IP protocol, supported by the IP layer 1213. The L2 layer 1212 andthe L1 layer 1211 may refer to communication links (e.g., wired orwireless) used by the RAN node and the MME to exchange information.

The AN 111 and the MME 121 may utilize an S1-MME interface to exchangecontrol plane data via a protocol stack comprising the L1 layer 1211,the L2 layer 1212, the IP layer 1213, the SCTP layer 1214, and the S1-APlayer 1215.

FIG. 13 is a block diagram illustrating components, according to someexample embodiments, able to read instructions from a machine-readableor computer-readable medium (e.g., a non-transitory machine-readablestorage medium) and perform any one or more of the methodologiesdiscussed herein. Specifically, FIG. 13 shows a diagrammaticrepresentation of hardware resources 1300 including one or moreprocessors (or processor cores) 1310, one or more memory/storage devices1320, and one or more communication resources 1330, each of which may becommunicatively coupled via a bus 1340. For embodiments where nodevirtualization (e.g., NFV) is utilized, a hypervisor 1302 may beexecuted to provide an execution environment for one or more networkslices/sub-slices to utilize the hardware resources 1300.

The processors 1310 (e.g., a central processing unit (CPU), a reducedinstruction set computing (RISC) processor, a complex instruction setcomputing (CISC) processor, a graphics processing unit (GPU), a digitalsignal processor (DSP) such as a baseband processor, an applicationspecific integrated circuit (ASIC), a radio-frequency integrated circuit(RFIC), another processor, or any suitable combination thereof) mayinclude, for example, a processor 1312 and a processor 1314.

The memory/storage devices 1320 may include main memory, disk storage,or any suitable combination thereof. The memory/storage devices 1320 mayinclude, but are not limited to any type of volatile or non-volatilememory such as dynamic random access memory (DRAM), static random-accessmemory (SRAM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), Flashmemory, solid-state storage, etc.

The communication resources 1330 may include interconnection or networkinterface components or other suitable devices to communicate with oneor more peripheral devices 1304 or one or more databases 1306 via anetwork 1308. For example, the communication resources 1330 may includewired communication components (e.g., for coupling via a UniversalSerial Bus (USB)), cellular communication components, NFC components,Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components,and other communication components.

Instructions 1350 may comprise software, a program, an application, anapplet, an app, or other executable code for causing at least any of theprocessors 1310 to perform any one or more of the methodologiesdiscussed herein. The instructions 1350 may reside, completely orpartially, within at least one of the processors 1310 (e.g., within theprocessor's cache memory), the memory/storage devices 1320, or anysuitable combination thereof. Furthermore, any portion of theinstructions 1350 may be transferred to the hardware resources 1300 fromany combination of the peripheral devices 1304 or the databases 1306.Accordingly, the memory of processors 1310, the memory/storage devices1320, the peripheral devices 1304, and the databases 1306 are examplesof computer-readable and machine-readable media.

The following paragraphs describe examples of various embodiments.

Example 1 includes an apparatus for a user equipment (UE), including aradio frequency (RF) interface; and processing circuitry configured to:decode a plurality of Reference Signals (RSs) received from an accessnode via a plurality of beams of the access node for the plurality ofRSs; determine, based on the decoded RSs, first beam quality for each ofa predefined subset of beams among the plurality of beams; determinesecond beam quality for the predefined subset of beams based on all ofthe first beam quality; in response to the second beam quality beingbelow a predetermined threshold, determine, based on the decoded RSs,third beam quality for each of one or more beams among the plurality ofbeams that are not within the predefined subset; and encode, based onthe first and third beam quality, a message for transmission to theaccess node via the RF interface for beam management, wherein themessage identifies one or more beam indexes for one or moreSynchronization Signal (SS) blocks.

Example 2 includes the apparatus of Example 1, wherein the plurality ofRSs are a plurality of SS blocks or a plurality of Channel StateInformation Reference Signals (CSI-RSs).

Example 3 includes the apparatus of Example 1 or 2, wherein the firstbeam quality for each of the predefined subset of beams is determined bymeasuring a Reference Signal Receiving Power (RSRP), a Signal toInterference plus Noise Ratio (SINR), or Reference Signal ReceivingQuality (RSRQ) of the beam.

Example 4 includes the apparatus of Example 1 or 2, wherein the secondbeam quality is an average of all of the first beam quality.

Example 5 includes the apparatus of Example 1 or 2, wherein the thirdbeam quality for each of the one or more beams is determined bymeasuring a Reference Signal Receiving Power (RSRP), a Signal toInterference plus Noise Ratio (SINR), or Reference Signal ReceivingQuality (RSRQ) of the beam.

Example 6 includes the apparatus of Example 1 or 2, wherein each of thebeam indexes is a timing index carried by a Demodulation ReferenceSignal (DMRS) of a Physical Broadcast Channel (PBCH) of an SS blockassociated with the beam index.

Example 7 includes the apparatus of Example 1 or 2, wherein the messageis encoded for transmission via a Physical Uplink Control Channel(PUCCH), a Medium Access Control (MAC) Control Element (CE), or a RadioResource Control (RRC) signaling.

Example 8 includes the apparatus of Example 1 or 2, wherein the messagefurther identifies beam quality for each of one or more beamscorresponding to the one or more beam indexes.

Example 9 includes the apparatus of Example 2, wherein the messagefurther identifies one or more flags for the one or more beam indexes,and if the plurality of RSs are a plurality of SS blocks, each of theflags indicates one of: whether to recommend the access node to add anSS beam corresponding to the beam index associated with the flag intothe predefined subset for beam measurement; and whether to recommend theaccess node to remove an SS beam corresponding to the beam indexassociated with the flag from the predefined subset.

Example 10 includes the apparatus of Example 2, wherein the messagefurther identifies one or more flags for the one or more beam indexes,and if the plurality of RSs are a plurality of CSI-RSs, each of theflags indicates one of: whether to recommend the access node to add oneor more CSI-RS beams into the predefined subset based on the beam indexassociated with the flag for beam measurement; and whether to recommendthe access node to remove one or more CSI-RS beams from the predefinedsubset based on the beam index associated with the flag.

Example 11 includes the apparatus of Example 1 or 2, wherein for each ofRSs associated with the one or more beams not within the predefinedsubset, a data channel or dedicated signal is transmitted in a slot forthe RS.

Example 12 includes the apparatus of Example 1 or 2, wherein for each ofRSs associated with the predefined subset of beams, no data channel ordedicated signal is transmitted in a slot for the RS.

Example 13 includes the apparatus of Example 1 or 2, wherein theprocessing circuitry is further configured to encode an indicator fortransmission to the access node, wherein the indicator indicates themaximum number of beams to be measured by the UE in a frame or a timingwindow.

Example 14 includes an apparatus for an access node, including a radiofrequency (RF) interface; and processing circuitry configured to:determine a time density of a Tracking Reference Signal (TRS) based on asubcarrier spacing of a bandwidth part (BWP) in a current componentcarrier for a user equipment (UE); determine a frequency density of theTRS based on a bandwidth of the TRS; determine a quasi co-location (QCL)relationship of the TRS; and encode the TRS based on at least one of thetime density, the frequency density and the QCL relationship fortransmission to the UE via the RF interface.

Example 15 includes the apparatus of Example 14, wherein the timedensity indicates the number M of slots for the TRS.

Example 16 includes the apparatus of Example 15, wherein the number M ofslots for the TRS is determined by a higher layer signaling or aDownlink Control Information (DCI).

Example 17 includes the apparatus of Example 15, wherein the number ofsymbols for the TRS in each of the slots is predetermined or configuredby a higher layer signaling.

Example 18 includes the apparatus of Example 14, wherein the frequencydensity indicates the number N of subcarriers carrying the TRS in asymbol of a Physical Resource Block (PRB).

Example 19 includes the apparatus of Example 14, wherein the bandwidthof the TRS is determined based on at least one of: a bandwidth of theBWP, and the subcarrier spacing of the BWP.

Example 20 includes the apparatus of Example 14, wherein the QCLrelationship is pre-defined or configured by a higher layer signaling.

Example 21 includes the apparatus of Example 15, wherein the QCLrelationship indicates that the TRS is Quasi-Co-Located (QCLed) with aSynchronization Signal (SS) block or a Channel State InformationReference Signal (CSI-RS).

Example 22 includes the apparatus of Example 21, wherein the SS block orthe CSI-RS is within the BWP in the current component carrier.

Example 23 includes the apparatus of Example 21, wherein the SS block orthe CSI-RS is within another BWP in the current component carrier oranother component carrier, which is different from the BWP in thecomponent carrier for the TRS.

Example 24 includes the apparatus of Example 21, wherein the TRS istransmitted in M−1 consecutive slots before or after the SS block or theCSI-RS.

Example 25 includes the apparatus of Example 14, wherein the TRS istransmitted in a manner selected from a periodic manner, an aperiodicmanner, and a semi-persistent manner.

Example 26 includes the apparatus of Example 14, wherein the TRS isencoded in response to a higher layer signaling or a Downlink ControlInformation (DCI).

Example 27 includes the apparatus of Example 14, wherein the TRS isencoded in response to a request for the TRS received from the UE.

Example 28 includes an apparatus for a user equipment (UE), including aradio frequency (RF) interface; and processing circuitry configured to:decode a first Tracking Reference Signal (TRS) received from a firstaccess node via the RF interface, wherein the time density of the firstTRS is determined based on a subcarrier spacing of a bandwidth part(BWP) in a current component carrier for the UE, and the frequencydensity of the first TRS is determined based on a bandwidth of the firstTRS.

Example 29 includes the apparatus of Example 28, wherein the processingcircuitry is further configured to encode a request for the first TRSfor transmission to the first access node.

Example 30 includes the apparatus of Example 29, wherein the request istransmitted via one of a Physical Random Access Channel (PRACH), aPhysical Uplink Control Channel (PUCCH), and a higher layer signaling.

Example 31 includes the apparatus of any of Examples 28-30, wherein theprocessing circuitry is further configured to: determine a gap period;and decode a second TRS received from a second access node during thegap period, wherein during the gap period, no data is transmitted fromthe first access node to the UE.

Example 32 includes a method performed at a user equipment (UE),including: decoding a plurality of Reference Signals (RSs) received froman access node via a plurality of beams of the access node for theplurality of RSs; determining, based on the decoded RSs, first beamquality for each of a predefined subset of beams among the plurality ofbeams; determining second beam quality for the predefined subset ofbeams based on all of the first beam quality; in response to the secondbeam quality being below a predetermined threshold, determining, basedon the decoded RSs, third beam quality for each of one or more beamsamong the plurality of beams that are not within the predefined subset;and encoding, based on the first and third beam quality, a message fortransmission to the access node for beam management, wherein the messageidentifies one or more beam indexes for one or more SynchronizationSignal (SS) blocks.

Example 33 includes the method of Example 32, wherein the plurality ofRSs are a plurality of SS blocks or a plurality of Channel StateInformation Reference Signals (CSI-RSs).

Example 34 includes the method of Example 32 or 33, wherein the firstbeam quality for each of the predefined subset of beams is determined bymeasuring a Reference Signal Receiving Power (RSRP), a Signal toInterference plus Noise Ratio (SINR), or Reference Signal ReceivingQuality (RSRQ) of the beam.

Example 35 includes the method of Example 32 or 33, wherein the secondbeam quality is an average of all of the first beam quality.

Example 36 includes the method of Example 32 or 33, wherein the thirdbeam quality for each of the one or more beams is determined bymeasuring a Reference Signal Receiving Power (RSRP), a Signal toInterference plus Noise Ratio (SINR), or Reference Signal ReceivingQuality (RSRQ) of the beam.

Example 37 includes the method of Example 32 or 33, wherein each of thebeam indexes is a timing index carried by a Demodulation ReferenceSignal (DMRS) of a Physical Broadcast Channel (PBCH) of an SS blockassociated with the beam index.

Example 38 includes the method of Example 32 or 33, wherein the messageis encoded for transmission via a Physical Uplink Control Channel(PUCCH), a Medium Access Control (MAC) Control Element (CE), or a RadioResource Control (RRC) signaling.

Example 39 includes the method of Example 32 or 33, wherein the messagefurther identifies beam quality for each of one or more beamscorresponding to the one or more beam indexes.

Example 40 includes the method of Example 33, wherein the messagefurther identifies one or more flags for the one or more beam indexes,and if the plurality of RSs are a plurality of SS blocks, each of theflags indicates one of: whether to recommend the access node to add anSS beam corresponding to the beam index associated with the flag intothe predefined subset for beam measurement; and whether to recommend theaccess node to remove an SS beam corresponding to the beam indexassociated with the flag from the predefined subset.

Example 41 includes the method of Example 33, wherein the messagefurther identifies one or more flags for the one or more beam indexes,and if the plurality of RSs are a plurality of CSI-RSs, each of theflags indicates one of: whether to recommend the access node to add oneor more CSI-RS beams into the predefined subset based on the beam indexassociated with the flag for beam measurement; and whether to recommendthe access node to remove one or more CSI-RS beams from the predefinedsubset based on the beam index associated with the flag.

Example 42 includes the method of Example 32 or 33, wherein for each ofRSs associated with the one or more beams not within the predefinedsubset, a data channel or dedicated signal is transmitted in a slot forthe RS.

Example 43 includes the method of Example 32 or 33, wherein for each ofRSs associated with the predefined subset of beams, no data channel ordedicated signal is transmitted in a slot for the RS.

Example 44 includes the method of Example 32 or 33, wherein the methodfurther includes encoding an indicator for transmission to the accessnode, wherein the indicator indicates the maximum number of beams to bemeasured by the UE in a frame or a timing window.

Example 45 includes a method performed at an access node, including:determining a time density of a Tracking Reference Signal (TRS) based ona subcarrier spacing of a bandwidth part (BWP) in a current componentcarrier for a user equipment (UE); determining a frequency density ofthe TRS based on a bandwidth of the TRS; determining a quasi co-location(QCL) relationship of the TRS; and encoding the TRS based on at leastone of the time density, the frequency density and the QCL relationshipfor transmission to the UE.

Example 46 includes the method of Example 45, wherein the time densityindicates the number M of slots for the TRS.

Example 47 includes the method of Example 46, wherein the number M ofslots for the TRS is determined by a higher layer signaling or aDownlink Control Information (DCI).

Example 48 includes the method of Example 46, wherein the number ofsymbols for the TRS in each of the slots is predetermined or configuredby a higher layer signaling.

Example 49 includes the method of Example 45, wherein the frequencydensity indicates the number N of subcarriers carrying the TRS in asymbol of a Physical Resource Block (PRB).

Example 50 includes the method of Example 45, wherein the bandwidth ofthe TRS is determined based on at least one of: a bandwidth of the BWP,and the subcarrier spacing of the BWP.

Example 51 includes the method of Example 45, wherein the QCLrelationship is pre-defined or configured by a higher layer signaling.

Example 52 includes the method of Example 46, wherein the QCLrelationship indicates that the TRS is Quasi-Co-Located (QCLed) with aSynchronization Signal (SS) block or a Channel State InformationReference Signal (CSI-RS).

Example 53 includes the method of Example 52, wherein the SS block orthe CSI-RS is within the BWP in the current component carrier.

Example 54 includes the method of Example 52, wherein the SS block orthe CSI-RS is within another BWP in the current component carrier oranother component carrier, which is different from the BWP in thecomponent carrier for the TRS.

Example 55 includes the method of Example 52, wherein the TRS istransmitted in M−1 consecutive slots before or after the SS block or theCSI-RS.

Example 56 includes the method of Example 45, wherein the TRS istransmitted in a manner selected from a periodic manner, an aperiodicmanner, and a semi-persistent manner.

Example 57 includes the method of Example 45, wherein the TRS is encodedin response to a higher layer signaling or a Downlink ControlInformation (DCI).

Example 58 includes the method of Example 45, wherein the TRS is encodedin response to a request for the TRS received from the UE.

Example 59 includes a method performed at a user equipment (UE),including: decoding a first Tracking Reference Signal (TRS) receivedfrom a first access node, wherein the time density of the first TRS isdetermined based on a subcarrier spacing of a bandwidth part (BWP) in acurrent component carrier for the UE, and the frequency density of thefirst TRS is determined based on a bandwidth of the first TRS.

Example 60 includes the method of Example 59, wherein the method furtherincludes encoding a request for the first TRS for transmission to thefirst access node.

Example 61 includes the method of Example 60, wherein the request istransmitted via one of a Physical Random Access Channel (PRACH), aPhysical Uplink Control Channel (PUCCH), and a higher layer signaling.

Example 62 includes the method of any of Examples 59-61, wherein themethod further includes: determining a gap period; and decoding a secondTRS received from a second access node during the gap period, whereinduring the gap period, no data is transmitted from the first access nodeto the UE.

Example 63 includes a computer-readable medium having instructionsstored thereon, the instructions when executed by one or moreprocessor(s) causing the processor(s) to perform the method of any ofExamples 32-62.

Example 64 includes an apparatus for a user equipment (UE), includingmeans for performing the actions of the method of any of Examples 32-44and 59-62.

Example 65 includes an apparatus for an access node (AN), includingmeans for performing the actions of the method of any of Examples 45-58.

Example 66 includes a user equipment (UE) as shown and described in thedescription.

Example 67 includes an access node (AN) as shown and described in thedescription.

Example 68 includes a method performed at a user equipment (UE) as shownand described in the description.

Example 69 includes a method performed at an access node (AN) as shownand described in the description.

Although certain embodiments have been illustrated and described hereinfor purposes of description, a wide variety of alternate and/orequivalent embodiments or implementations calculated to achieve the samepurposes may be substituted for the embodiments shown and describedwithout departing from the scope of the present disclosure. Thisapplication is intended to cover any adaptations or variations of theembodiments discussed herein. Therefore, it is manifestly intended thatembodiments described herein be limited only by the appended claims andthe equivalents thereof.

What is claimed is:
 1. An apparatus for a user equipment (UE),comprising baseband processing circuitry configured to: determine anumber of slots for a Tracking Reference Signal (TRS), wherein thenumber of slots is based on a subcarrier spacing of a bandwidth part(BWP) in a current component carrier for the UE; and receive TRS basedon the number of slots and a quasi co-location (QCL) relationship of theTRS, wherein the QCL relationship indicates that the TRS isQuasi-Co-Located (QCLed) with a Synchronization Signal (SS) block or aChannel State Information Reference Signal (CSI-RS).
 2. The apparatus ofclaim 1, wherein a bandwidth of the TRS is determined based on at leastone of a bandwidth of a bandwidth part (BWP), and a subcarrier spacingof the BWP.
 3. The apparatus of claim 1, wherein the QCL relationship ispre-defined or configured by a higher layer signaling.
 4. The apparatusof claim 1, wherein the CSI-RS is within a bandwidth part (BWP) in acurrent component carrier.
 5. The apparatus of claim 1, wherein theCSI-RS is within another bandwidth part (BWP) in a current componentcarrier or another component carrier, which is different from a BWP in acomponent carrier for the TRS.
 6. The apparatus of claim 1, wherein anumber of symbols for the TRS in each slot is configured by a higherlayer signaling.
 7. The apparatus of claim 1, wherein the basebandprocessing circuitry is configured to cause the UE to transmit a requestfor TRS via a Physical Random Access Channel (PRACH).
 8. The apparatusof claim 1, wherein the baseband processing circuitry is configured tocause the UE to receive downlink control information (DCI) thatindicates the number of slots for the TRS.
 9. A method for a userequipment (UE), comprising: determining a number of slots for a TrackingReference Signal (TRS), wherein the number of slots is based on asubcarrier spacing of a bandwidth part (BWP) in a current componentcarrier for the UE; and receiving TRS based on the number of slots and aquasi co-location (QCL) relationship of the TRS, wherein the QCLrelationship indicates that the TRS is Quasi-Co-Located (QCLed) with aSynchronization Signal (SS) block or a Channel State InformationReference Signal (CSI-RS).
 10. The method of claim 9, wherein aabandwidth of the TRS is determined based on at least one of a bandwidthof a bandwidth part (BWP), and a subcarrier spacing of the BWP.
 11. Themethod of claim 9, wherein the QCL relationship is pre-defined orconfigured by a higher layer signaling.
 12. The method of claim 9,wherein the CSI-RS is within a bandwidth part (BWP) in a currentcomponent carrier.
 13. The method of claim 9, wherein the CSI-RS iswithin another bandwidth part (BWP) in a current component carrier oranother component carrier, which is different from a BWP in a componentcarrier for the TRS.
 14. The method of claim 9, wherein a number ofsymbols for the TRS in each slot is configured by a higher layersignaling.
 15. The method of claim 9, comprising transmitting a requestfor TRS via a Physical Random Access Channel (PRACH).
 16. The method ofclaim 9, further comprising receiving downlink control information (DCI)that indicates the number of slots for the TRS.
 17. A base station,comprising one or more processors configured to: determine a number ofslots for a Tracking Reference Signal (TRS), wherein the number of slotsis based on a subcarrier spacing of a bandwidth part (BWP) in a currentcomponent carrier for a user equipment (UE); and transmit TRS to the UEbased on the number of slots and a quasi co-location (QCL) relationshipof the TRS, wherein the QCL relationship indicates that the TRS isQuasi-Co-Located (QCLed) with a Synchronization Signal (SS) block or aChannel State Information Reference Signal (CSI-RS).
 18. The basestation of claim 17, wherein a bandwidth of the TRS is determined basedon at least one of a bandwidth of a bandwidth part (BWP), and asubcarrier spacing of the BWP.
 19. The base station of claim 17, whereinthe QCL relationship is pre-defined or configured by a higher layersignaling.
 20. The base station of claim 17, wherein the CSI-RS iswithin a bandwidth part (BWP) in a current component carrier.
 21. Thebase station of claim 17, wherein the CSI-RS is within another bandwidthpart (BWP) in a current component carrier or another component carrier,which is different from a BWP in a component carrier for the TRS. 22.The base station of claim 17, wherein a number of symbols for the TRS ineach slot is configured by a higher layer signaling.
 23. The basestation of claim 17, wherein the one or more processors are configuredto cause the base station to transmit the TRS in response to a receivedrequest for a TRS from the UE via a Physical Random Access Channel(PRACH).
 24. The base station of claim 17, wherein the one or moreprocessors are configured to cause the base station to transmit downlinkcontrol information (DCI) that indicates the number of slots for theTRS.